1. Field of the Invention
An apparatus consistent with the present invention relates to a servo writer for recording/reproducing servo signals on or from tape-shaped recording media such as magnetic tapes.
2. Description of the Related Art
In recent years, the recording density of magnetic tapes used as data back-up media for computers has been increased. This increase in the recording density has been realized by increasing the number of data tracks formed on a single magnetic tape. For the purpose of reading data from such high density magnetic tapes with great accuracy, multiple servo bands are formed on both sides of each data track. Note that the servo band is a region to/from which a servo signal is to be recorded or reproduced.
Such servo signals need to be written (recorded) precisely on magnetic tapes by using a magnetic tape system such as a servo writer.
FIG. 7 shows an example of a peripheral structure of a servo write head in a conventional servo writer. In this figure, this structure includes a base 51, a support arm 52, and a servo write head 50. The support arm 52 is coupled to the base 51 and has a free end 52a. A servo write head 50 is placed on the free end 52a and has a head surface 50a facing a recording surface of a magnetic tape MT. The support arm 52 has a position adjusting means made up of precision components, and it adjusts the position of the servo write head 50 with respect to the magnetic tape MT. The position adjusting means includes a tape-width direction adjusting mechanism 53a, a lap angle adjusting mechanism 53b, an azimuth angle adjusting mechanism 53c, and a tilt angle adjusting mechanism 53d. By turning their individual knobs, the position of the servo write head 50 with respect to the magnetic tape MT can be adjusted. Thus, servo signals are recorded on desired locations of the magnetic tape MT.
Another example of this mechanism is described in Japanese Unexamined Patent Application Publication 2001-093211. In the exemplified mechanism, the servo write head is fixed, a magnetic tape is movable, and its position is adjustable. Further, by adjusting the position of the magnetic tape, servo signals are recorded on desired locations of the magnetic tape.
Referring back to FIG. 7, each of the adjusting mechanisms 53a to 53d in the conventional servo writer needs to be precise, and inevitably involves high costs. In addition, to adjust the position of the servo write head 50, its lap and tilt angles need to be adjusted appropriately, but this adjustment has the following disadvantage.
The adjustable range of the lap angle θ needs to fall within 5.0°±0.5° (each side 2.5°±0.5°) with respect to the head surface 50a of the servo write head 50, as shown in FIG. 8. Since this range is very narrow, it takes a long time adjusting. In addition, costs for maintaining this lap angle θ end up being high.
On the other hand, by adjusting the tilt angle, one side of the magnetic tape MT along its length is pressed against the servo write head 50 more strongly than the other side. Accordingly, the displacement amount of the magnetic tape MT is advantageously decreased, but the head surface 50a is prone to wear unevenly. Furthermore, magnetic powder of the magnetic tape MT is more likely to be stuck on the head surface 50a, thus increasing the occurrence of recording/reproducing errors.
Taking the above disadvantage into account, the present invention has been conceived. An object of the present invention is to provide a low cost servo writer with a simple adjusting mechanism, which can record/reproduce servo signals on or from magnetic tapes with great accuracy. An additional object of the present invention is to provide a servo writer which makes it possible to shorten the adjusting and maintenance time and to minimize the uneven wear of its head, thereby decreasing the level of contaminants of the heads (servo write head and the like).